High pressure, ambient temperature gas storage and delivery devices have been heretofore suggested for providing attitude independent supply of mixed gasses such as breathable air to a user thereof. Such devices, while in use, have limited gas delivery time, are bulky, and must be operated at extremely high pressures.
Liquid air storage and delivery devices have also been suggested (see U.S. Pat. Nos. 1,448,590, 3,318,307, 3,570,481, 3,572,048, 4,181,126, 3,699,775, 1,459,158, and 3,227,208), but suffer from limited standby time due to oxygen enrichment inherent in such storage, some being unduly complex in an effort to confront this problem, are not attitude independent, and are often quite heavy.
A dispenser for cryogenic temperature elemental and compound gasses (below -175.degree. F.) such as oxygen held for use at supercritical pressure (above 730 psia) has been heretofore suggested (see U.S. Pat. No. 3,062,017) wherein a primary, active heat transfer mechanism (i.e., an electrical heating element, as opposed to a passive heat exchanger as set forth hereinbelow) is utilized to pressurize the storage vessel having liquid oxygen loaded therein at atmospheric pressure (thus making the dispenser less than desirable as an air supply, where oxygen enrichment could occur while liquid air is in standby storage) for expelling the oxygen.
Pressure sensing is thereafter used to sense the heat transfer needs in the vessel to maintain pressure therein above critical pressure by activating the heating element periodically. An auxiliary passive heat exchanger is provided for situations where power becomes unavailable, but only for use in maintaining pressure, the passive system being, apparently, incapable of reasonably initiating vessel pressurization. The passive heat exchange is done utilizing means separate from the dewar and remains encumbered by complex sensing and activating mechanisms (blinds for admitting or shutting out radiant energy) to assure proper heat input. Improvement in such dispensers could thus still be utilized.
A variety of loading, conditioning or recovery devices have been heretofore suggested for use with various fluid storage devices (see U.S. Pat. Nos. 4,049,409, 3,354,664, 4,274,851 and 4,326,867). Such heretofore known devices have not been particularly well adapted for use in storage of cryogenic temperature gas at supercritical pressure. Nor have such devices been provided which are self-contained and portable as would be desired for emergency facility or personnel use. Further improvement is thus warranted.